不同分子结构与分子质量HCS的湿部化学行为

Influences of Configuration and Molecular Weight of Highly Cationic Starches on Their Wet-end Performances and Paper Strengthening Effects

采用普通淀粉、支链淀粉和直链淀粉制备不同分子结构的高取代度阳离子淀粉(HCS),再采用酸降解法减小HCS的分子质量,探讨了分子结构、分子质量等因素对HCS湿部化学行为和纸张增强效果的影响。结果表明,在相同用量条件下,与降解前相比,降解后的HCS更容易被纤维吸附,其助滤效果更好;而且降解程度越大的HCS会越多地与浆料液相中的胶体物质作用。在纸张强度方面,添加降解和未降解的HCS均使手抄片的抗张指数得到维持甚至得到一定程度的提高,耐破指数基本没有变化;降解与未降解的普通HCS、直链HCS均使耐折度、撕裂度有一定程度的下降,但是支链HCS(不管降解与否)均能较好地维持这两项指标。

Normal starch, amylose and amylopectin were used to prepare highly cationic starches （HCSs） with different configurations which were named as normal, linear and branched HCSs. The starches were degraded with acid hydrolysis in order to obtain a series of HCSs with lower and various molecular weights. The influences of configuration and molecular weight of the starches on their wet end performances and paper strengthening effects were investigated. Comparing with the undegraded HCSs at the same dosage level （weight base）, it was found that the degraded HCSs are easier to be adsorbed onto fibers; it leads to better drainage and colloidal substances removal of the pulp. With respect to the strengthening properties, it was discovered that tensile index can be maintained or even increased by all the HCSs while burst index changes very little; the degraded normal and linear HCSs decreases folding endurance slightly and tearing index to some extent, but the branched HCSs, either degraded or not, can maintain these two properties well.